I put 2 honeywell RTH221 thermostats in to replace old mercury thermostats on a hot water system. There are 2 zones, 2 thermostats but 1 pump on the boiler. The pump seems to cycle on and off frequently. The function cycle is set at 3 as recommended. Should the pump be cycling on and off like this? I was told by tech support that this is because it keeps it within 1 degree of set temperature. How often should this pump cycle on and off and when is it too much?
Heating & Cooling - Honeywell - Programmable Thermostat Heater
Answers & Comments
Hi,
You can change the function cycle but you may give up some comfort...the longer the cycles the more the temp. will swing between cycles...
So the answer is that no the shorter cycles do not really hurt anything... yes there is a bit more wear and tear on the equipment, and a slight decrease in efficiency, but no real problems....
If you would like to try the longer cycles then change it and see what happens... just go 1 number at a time and time the cycles to see what difference the change makes... remember though that outside temps.(heat loss and gain) can also effect the cycles...
If I were you I would be experimenting a bit and see what you like and are satisfied with...
heatman101